Telegraphic transmitter



' M. H. DEMENT.

, TEL'EGRAPHIG TRANSMITTER. No. 287,914. Patented Nov. 6, 1883..

I f f nrrnn STATE ATENT Fries.

MERBITT H. 'DEMENI, OF CHICAGO, ILLINOIS.

TELEGRA PHIC TRANSMITTER.

SPECIFICATION forming part of LettersIEatent No. 287,914, dated November6, 1883.

Application filed January 3, 1883. (No model.)

To all whom it mag concern.-

Be it known that I, Mnnnrr'r H. Dnrrnnr,

of the city of Chicago, county of Cook, and State of Illinois, haveinvented a new and useful Telegraph Transmitting Apparatus, of

which the following is a specificatiom'referthe improvement consistingin a device and mechanism whereby each letter of the alphabetorsymholmay be transmitted by a' single depression of a key instead offrom one to eight depressions, as at present.

By means of my improvement messages may be transmitted more rapidly thanat present, and the dotsand dashes made with mechanical accuracy; and mytransmitter requires no specialmannal dexterity in operation, and may bepractically operated by a person who has no'special knowledge oftelegraphy.

My invention consists of an apparatus for transmitting telegraphicmessages, having a s'eriesof keys representing letters or symbols, eachkey being provided with a notched plate corresponding to the dots anddashes representing the particular letter in a telegraphic alphabet. betbe followed, the key for the letter D would i have one wide and twonarrow faces, representing a dash and two dots, while the key for theletter would have'five narrow faces, representing five dots.

In the annexed drawings, Figure 1 is what maybetermed a sectional viewofithe transmitter, showing two keys, A and B, hung on a pivotal bar d,the bar being secured in shoulders at each end of the support 6. -0nekeyisshown in position and the other partially depressed. Pivotedto thekeys and underneath them are arms which are so arranged as to be capableof a slightswinging move ment. To thearms there are secured platesnotched so as to have long and short faces, (each plate beingdifferenu)corresponding to the dots and dashes of a telegraph-alphabet.

E E represent plates of copper or other suit able material, insulated bynon-conducting blocks a a, and connected with the maintransmitting-wire.

For instance, if the Morse alpha-- as to hold the plate I against theblocks a a, and the copper plate E, so that the faces on the former willbe sure to touch the latter and make the circuit as the key isdepressed.

The spring F, a detailed view of which is shown in-Fig. 3, is used toprevent the plate I from passing over the copper plate E in its upwardor return movement.

The arm 0 is provided with a cam-pin, J, which, as the key is depressed,slides along the shoulder shown on the spring F in Fig. 3, thus pressingthe spring back until the cam passes the lower part of the shoulder onthe turns to position with its lower end resting against the block; andwhen the key is lifted y catches behind the shoulder of the spring F,and passes up until it reaches the top of the "shoulder, thespringmeanwhile being held with sufficient firmness by the lower point restingagainst the plateb to throw the arm 0, as it ascends, back and away fromthe plate E until the cam J on the arm 0 shall have risen to a pointhigher than the shoulder on the spring F, at which time the arm G willbe released, and the spring H operates to'throw and hold the arm 0 backagainst the block a in position to be again operated upon. Theblocks b bare stops against which the key-arm C strikes, and against which alsothe lower point of the spring F rests, one purpose being to give thespring rigidity enough to throw the The spring G operates upon the arm0, so I spring, when the spring is released and rep the action of thespring H the cam J i arm G back when the cam J catches behind the shoulder, of the spring.

Fig. 2 is a detail view of a notched plate, showing long and shortfaces. By the side of it are also represented the dots and dashes asthey would appear upon the paper slip at the receiving-station after thenotched plate here shown has operated upon the plate E.

Fig. 4 is a plan view of a portion of the transmitter, showingarrangement of keys.

In a full-sized machine there would be fortyfive or more keys. To makethem compact two wires may be used, as here shown, the arms upon thefirst and each alternate key operating upon one wire, and the remainderof the keys upon the other, the twowires being connected with the maintransmitting-wire;

' or, if desired, the keys may be so arranged as to have the arms form acircle, using but one pressing the key representing the letter to betransmitted, and'thereby causing the notched plate attached to the armunderneath the key to pass across the plate or wire E, the circuit beingclosed, as the faces of the plate pass, for a short or long period, asthe faces are wide or narrow, and the circuit being opened between thefaces while the openings or notches are passing. A wide face wouldoccupy a longer time inpassing the plate E, and would make a dash at thereceiving-station, while the narrow face would occupy a shorter time,and would make dots. The messages sent by this transmitter are intendedto be received upona continuous strip of paper at the receiving-stationin dots and dashes, which may be transcribed at convenience.

The plate I may have the spaces between the faces therein filled withnon-conducting material instead of being left open, and thetransmitting-wire in such case need not be incased by'the blocks a a,but may be made more protruding. The transmitter may also be made toaccomplish the same object by placing the notched plates upon a supportconnecting them with the transmitting-wire, and providing the arm 0 witha single point, narrower than the openings or spaces between the faceson the plates, and as the key is de- I pressed the circuit will beclosed and opened as the point on the arm 0 comes in contact with thefaces or passes the intervening openings in the plates. The transmitter,when made in this way, will accomplish substantially the same result asif made as hereinbefore described, and is fully within the spirit of myinvention. d

I am aware that patents have. heretofore been granted for the use ofsimilar notched plates or series of metal blocks; but I believe that themeans herein described of adapting such a device to practical telegraphyare superior to any heretofore devised.

Having thus fully described my invention, what I claim as new, anddesireto secure by Letters Patent, is

1. The combination of the key A, arm Q, plate I, spring G, atransmitting-wire, cam J, spring F, and spring H, substantially as andfor the purposes shown and described.

2.- A telegraph-key provided with'a hinged arm, and means for pressingthe arm against the transmitting-wireas the key'is depressed, incombination with the cam J and spring F, substantially as and for thepurposes shown and described.

3. In a telegraph=transmitter, a key pro vided with a hinged arm havinga cam, J, in

